<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>

<div>
  <input type="text" v-model="n1">
  <input type="text" v-model="n2">
  <input type="button" value="加" @click="f(1)">
  <input type="button" value="减" @click="f(2)">
  <input type="button" value="乘" @click="f(3)">
  <input type="button" value="除" @click="f(4)">
  <h3>结果:{{result}}</h3>
</div>

<script src="js/vue.min.js"></script>
<script>
  let v= new Vue({
    el:"body>div",
      data:{
        n1:"",
          n2:"",
          result:""
      },
      methods:{
        f(x){
            switch (x) {
                case 1:
                    v.result=v.n1*1+v.n2*1;
                    break;
                case 2:
                    v.result=v.n1-v.n2;
                    break;
                case 3:
                    v.result=v.n1*v.n2;
                    break;
                case 4:
                    v.result=v.n1/v.n2;
                    break;

            }
        }
      }

  })
</script>
</body>
</html>